M.A.G. Engine - Three-speed Counter-shaft Gear - Chain Drive Throughout.
THERE are no men in the motor cycle business who have had greater experience in the use and construction of racing motor cycles than Messrs. H. A. and C. R. Collier. From the very earliest days of the movement we used to watch with interest the wonderful performances of these intrepid riders on Canning Town track, which was only banked for 40 m.p.h., but even in those early days they used easily to exceed the limit of speed on carefully built and well tuned 2¾ h.p. racing machines. It is not surprising, therefore, to note that the 1915 3½ h.p. Matchless racer is a beautiful piece of design, capable of obtaining the highest possible speeds, and of standing up under the most strenuous tests. The machine we are about to describe was primarily built for the 1915 Tourist Trophy.
The 3½ h.p. engine, 496 c.c, 64 mm. x 77 mm., remains practically unaltered; it is an exquisite piece of work and beautifully finished. The most important improvements on the machine are the introduction of chain transmission and the fitting of a three-speed counter-shaft gear box, which contains gears of the sliding type.
The magneto bracket forms part of the gear box casting, and the bolts holding the magneto on to the bracket pass through slotted holes so that in the event of it being necessary to take down the engine the magneto can be slid backwards, the tailshaft dropped out, and the engine removed without further disturbing the magneto. The magneto itself is in an ideal position, and is well out of the way of mud and wet.
The Transmission.
Reverting to the gear box, it is interesting to note that if the end plate be removed the gear ratios may be changed by removing the layshaft and loose pinion and replacing them, and arrangements have been made to supply three separate sets of gear ratios, which are as follow: 3½, 4½, and 5½ to 1, and two sets in which the third and second speeds remain the same, but in which the low speeds are 6¼ and 7½ to 1 respectively.
As regards the chain transmission, an ingenious and effective form of shock absorber is fitted to the engine-shaft. The nature of this may be clearly seen from the accompanying sketch. It will be obvious that the sprocket is engaged with the extension of the engine-shaft by means of inclined planes which slide on a feather solidly attached to the shaft.
These planes are kept in engagement by means of a strong spring, but on the engine accelerating there is a tendency for the sprocket to force the sleeve on which the inclined planes are cut backwards and so give just the right amount of slip to absorb all sudden stresses on the chains. The bolt at the end of the mechanism acts as a grease cup, and if grease be injected it lubricates the device adequately for a season's running. A further shock absorber is fitted to the back sprocket which takes the form of a rubber cushioned drive, with the result that the transmission in the racing Matchless should be as elastic as if a belt were fitted.
The general view of the machine shows the well designed silencer and the easy sweep of the exhaust pipes, which to conduct away the gases with the minimum amount of back pressure. The whole machine is finished in khaki, a serviceable and businesslike colour, even to the back hub. The gear box, we may mention, is practically the same as that fitted to the sidecar combination with the exception that no kick starter is provided. When the time comes to put the racing Matchless to the test we do not hesitate to say that we think it will give an excellent account of itself.
The Motor Cycle, October 29th, 1914. p486.
